This invention relates to a cleaning apparatus for use in an electrostatographic reproducing machine. The cleaning apparatus is particularly adapted for removing magnetic particles from an imaging surface in order to clean the surface. Alternatively the cleaning apparatus can be used to remove magnetic particles from a conventional cleaning device which in turn removes the particles from the imaging surface.
The use of magnetic toner particles for developing electrostatic images is well known in the art. For example, U.S. Pat. No. 2,846,333 to Wilson teaches the use of a single component magnetic developer material which is applied directly to a photoconductive surface for development. U.S. Pat. No. 3,909,258 to Kotz also discloses the use of a single component developer for developing electrostatic images. The magnetic toner particles may be conductive or non-conductive.
Conventional cleaning devices known in the art comprise brushes, webs, rollers, blades, etc., as exemplified by the following U.S. Pat. Nos. 3,655,373 to Fisher; 3,099,856 to Eichorn et al.; 3,807,853 to Hudson; and 3,634,072 to Sullivan.
Various reverse development approaches to cleaning are known which include the use of magnetic brush cleaning as exemplified in the following U.S. Pat. Nos. 2,956,487 to Giamo and 3,580,673 to Yang.
Of particular interest with respect to the present invention is U.S. Pat. No. 3,659,311 to Waren which discloses a device for scavenging magnetizable powder from a drum in a printing apparatus. The powder is attracted from the drum to the surface of a non-magnetic tube positioned parallel to the drum. A rotatable set of adjacent magnets is contained within the tube. The rotation of the magnets causes a divergent magnetic flux field to attract the magnetizable powder and to work the powder around the surface of the tube in a direction opposite to the magnet rotation and onto a ledge extention of the tube surface so that it may fall into a collection trough.
While it is known to employ magnetizable or magnetic toner particles for developing electrostatic images in electrostatic reproducing machines the fullest advantage has not been taken of the magnetizable nature of the particles to aid in their removal from an imaging surface or the cleaning device used for such removal.